PHP＆MySql：无法更新数据库

问题描述：

I'm working on a project where I need to set the boolean value isHere to true(1) when it finds the corresponding ID. However I can't seem to update the database. I can select from the database though.

I have two problems. First:

$handle = @fopen("../smartriders.txt", "r");

    if ($handle) 
        {
        while (($smartRider = fgets($handle, 255)) !== false) 
        { 

            if($update = $conn->query("UPDATE members SET isHere = 1 WHERE SmartRiderID = ?", $smartRider))
            {
                print("update successful");
            }
        }
        if (!feof($handle)) {
            echo "Error: unexpected fgets() fail
";
        }
        fclose($handle);
    }

This yields a warning:

Warning: mysqli::query() expects parameter 2 to be integer, string given in index.ph on line 14.

line 14:

if($update = $conn->query("UPDATE members SET isHere = 1 WHERE SmartRiderID = ?", $smartRider))

the second problem: Even if I manually type the smartRider that is in the database, nothing gets updated.

Any help would really be appreciated.

答

If you refer to mysqli_query manual - you will see that second argument of this function is int $resultmode.

See - it is int. And it's purpose is to define a structure of returned result. So, passing your $smartRider to query() is useless.

query function doesn't work with prepared statements.

For prepared statements is prepare():

$stmt = $mysqli->prepare('UPDATE members SET isHere = 1 WHERE SmartRiderID = ?');
$stmt->bind_param('s', $smartRider);
$res = $stmt->execute();

For cheking result of execute() see http://php.net/manual/en/mysqli-stmt.execute.php.

答

problem1: Warning: mysqli::query() expects parameter 2 to be integer, string given in index.ph on line 14.

solution:

if($update = $conn->query("UPDATE members SET isHere = 1 WHERE SmartRiderID = " . $smartRider))

PHP＆MySql：无法更新数据库

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